This invention relates to catheter and needle assemblies.
When a catheter is inserted in a vein or similar part of the body, this is often performed using a needle inserted within the catheter. The patient end of the needle is sharp and protrudes from the patient end of the catheter. The patient end of the assembly of the catheter on the needle is inserted in the vein and the needle is subsequently removed, leaving the catheter in position. The needle may be removed through a self-sealing port at the machine end of the catheter; a separate port is used to provide fluid access to the vein. Such an assembly is described, for example, in GB 2088215.
After the needle has been removed from the catheter, its patient end will carry traces of blood, which presents a potential contamination risk to the clinician and to people subsequently handling the needle. In order to protect the tip of the needle from contact after it has been withdrawn from the catheter, it has been proposed that the needle be withdrawn into a tubular protector after use, in the manner described in EP 54671 and EP 734272. In U.S. Pat. No. 4,978,344 there is described a tethered protective cap frictionally retained in a catheter hub so that it is pulled off the catheter and retained with the needle when the needle is pulled out of the catheter hub. One problem with previous arrangements has been that it is possible for the needle to be removed from the catheter before the needle has been withdrawn into, or fully withdrawn into the protector.